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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
321

High-Level Parallel Programming of Computation-Intensive Algorithms on Fine-Grained Architecture

Cheema, Fahad Islam January 2009 (has links)
<p>Computation-intensive algorithms require a high level of parallelism and programmability, which </p><p>make them good candidate for hardware acceleration using fine-grained processor arrays. Using </p><p>Hardware Description Language (HDL), it is very difficult to design and manage fine-grained </p><p>processing units and therefore High-Level Language (HLL) is a preferred alternative. </p><p> </p><p>This thesis analyzes HLL programming of fine-grained architecture in terms of achieved </p><p>performance and resource consumption. In a case study, highly computation-intensive algorithms </p><p>(interpolation kernels) are implemented on fine-grained architecture (FPGA) using a high-level </p><p>language (Mitrion-C). Mitrion Virtual Processor (MVP) is extracted as an application-specific </p><p>fine-grain processor array, and the Mitrion development environment translates high-level design </p><p>to hardware description (HDL). </p><p> </p><p>Performance requirements, parallelism possibilities/limitations and resource requirement for </p><p>parallelism vary from algorithm to algorithm as well as by hardware platform. By considering </p><p>parallelism at different levels, we can adjust the parallelism according to available hardware </p><p>resources and can achieve better adjustment of different tradeoffs like gates-performance and </p><p>memory-performance tradeoffs. This thesis proposes different design approaches to adjust </p><p>parallelism at different design levels. For interpolation kernels, different parallelism levels and </p><p>design variants are proposed, which can be mixed to get a well-tuned application and resource </p><p>specific design.</p>
322

Accelerator Mass Spectrometry of 36Cl and 129I : Analytical Aspects and Applications

Alfimov, Vasily January 2004 (has links)
Two long-lived halogen radionuclides (36Cl, T1/2 = 301 kyr, and 129I, T1/2 = 15.7 Myr) have been studied by means of Accelerator Mass Spectrometry (AMS) at the Uppsala Tandem Laboratory. The 36Cl measurements in natural samples using a medium-sized tandem accelerator (~1 MeV/amu) have been considered. A gas-filled magnetic spectrometer (GFM) was proposed for the separation of 36Cl from its isobar, 36S. Semi-empirical Monte-Carlo ion optical calculations were conducted to define optimal conditions for separating 36Cl and 36S. A 180° GFM was constructed and installed at the dedicated AMS beam line. 129I has been measured in waters from the Arctic and North Atlantic Oceans. Most of the 129I currently present in the Earth's surface environment can be traced back to liquid and gaseous releases from the nuclear reprocessing facilities at Sellafield (UK) and La Hague (France). The anthropogenic 129I inventory in the central Arctic Ocean was found to increase proportionally to the integrated 129I releases from these reprocessing facilities. The interaction and origin of water masses in the region have been clearly distinguished with the help of 129I labeling. Predictions based on a compartment model calculation showed that the Atlantic Ocean and deep Arctic Ocean are the major sinks for the reprocessed 129I. The variability in 129I concentration measured in seawater along a transect from the Baltic Sea to the North Atlantic suggests strong enrichment in the Skagerrak–Kattegat basin. The 129I inventory in the Baltic and Bothnian Seas is equal to ~0.3% of the total liquid releases from the reprocessing facilities. A lake sediment core sampled in northeastern Ireland was analyzed for 129I to study the history of the Sellafield releases, in particular the nuclear accident of 1957. High 129I concentration was observed corresponding to 1990 and later, while no indication of the accident was found. The results of this thesis research clearly demonstrate the uniqueness and future potential of 129I as a tracer of processes in both marine and continental archives.
323

臺灣新型創業加速育成機構的加值與網絡關係的研究 / Study of added value and network relationship of new startup accelerator in Taiwan

胡月, Steve Hu Unknown Date (has links)
創業加速器,作為一種新形態的創新育成組織單位,其宗旨在於為早期處於初創階段的團隊提供輔導並協助其發展。 本研究將創業加速器所提供的服務流程分成了兩個主要階段進行研究,涵蓋了從團隊篩選到最後的投後管理總共四個步驟。本研究採用個案深度訪談的方式來蒐集主要資料,並通過三角驗證進行比對,訪談了目前市場上三家代表性的創業加速器以及兩家相關初創團隊成員。 主要研究發現與結論如下: 1. 新型創業加速器在篩選環節,對於創業團隊中的核心成員的創業動機與決心會更加看重。 2. 台灣新型創業加速器所提供的加值服務,主要以非物質性的服務形態(業師經驗、課程培訓以及專業服務等)表現出來。 3. 創業加速器提供的Demo Day是相較於傳統育成中心最不一樣的地方,這種集中在一天,公開發表,聚集眾多業者的模式,也成為了與投資者媒合的重要機會。 4. 創業加速器所建構的網絡關係的價值在於幫助投資者降低投資風險,提高投資的成功率。 / Startup Accelerator, as a new form of incubation organization, is committed to serve for early stage team and help them grow up rapidly. The research is based on two main aspects of the incubation service covering the whole process from filtering teams to the post-demo day management respectively. The depth interview has been regarded as the research methodology of the thesis, including three representative startup accelerators and two teams incubated in these acclerators. The conlusion has been drawn up as below: 1. The priority of screening out of portfolio is the motivation and determination of co-founders. 2. The added-value service are mainly provided in the form of intangible assets such as mentoring, course training and professional knowledge support. 3. The Demo Day event held by startup accelerators which differentiate themselves from traditional incubation centers is a match-making platform for investors and entrepreneurs with open presentation to the public in one or two days. 4. The value of network relationship is to reduce investment risks.
324

Análisis de los mecanismos de emisión y de las correlaciones angulares de los productos de interacción del 0-16 a 2,1 gev/a con núcleos de emulsión

Ruiz Jimeno, Alberto 03 June 1978 (has links)
The interactions, with emulsion nuclei, of O-16 ions accelerated at 2.1 GeV/nucleon in the Berkeley accelerator, are analyzed. A phenomenological study of the events, particularly reaction cross sections and multiplicities is exposed to nuclear theories with nucleons acting individually and collectively An study of the angular distributions of the reaction products and their correlations, particularly in the transversal space, is shown. Finally, a discussion of the present parton model of the nucleon structure is done, comparing it with the experimental results.
325

High-Level Parallel Programming of Computation-Intensive Algorithms on Fine-Grained Architecture

Cheema, Fahad Islam January 2009 (has links)
Computation-intensive algorithms require a high level of parallelism and programmability, which make them good candidate for hardware acceleration using fine-grained processor arrays. Using Hardware Description Language (HDL), it is very difficult to design and manage fine-grained processing units and therefore High-Level Language (HLL) is a preferred alternative. This thesis analyzes HLL programming of fine-grained architecture in terms of achieved performance and resource consumption. In a case study, highly computation-intensive algorithms (interpolation kernels) are implemented on fine-grained architecture (FPGA) using a high-level language (Mitrion-C). Mitrion Virtual Processor (MVP) is extracted as an application-specific fine-grain processor array, and the Mitrion development environment translates high-level design to hardware description (HDL). Performance requirements, parallelism possibilities/limitations and resource requirement for parallelism vary from algorithm to algorithm as well as by hardware platform. By considering parallelism at different levels, we can adjust the parallelism according to available hardware resources and can achieve better adjustment of different tradeoffs like gates-performance and memory-performance tradeoffs. This thesis proposes different design approaches to adjust parallelism at different design levels. For interpolation kernels, different parallelism levels and design variants are proposed, which can be mixed to get a well-tuned application and resource specific design.
326

Testing and evaluation of the integratability of the Senior processor / Testning och evaluering av Senior processorns integrerbarhet

Hedin, Alexander January 2011 (has links)
The first version of the Senior processor was created as part of a thesis projectin 2007. This processor was completed and used for educational purposes atLinköpings University. In 2008 several parts of the processor were optimized andthe processor expanded with additional functionality as part of another thesisproject. In 2009 an EU funded project called MULTI-BASE started, in which theComputer Division at the Department of Electrical Engineering participated in.For their part of the MULTI-BASE project, the Senior processor was selected tobe used. After continuous revision and development, this processor was sent formanufacturing. The assignment of this thesis project was to test and verify the different func-tions implemted in the Senior processor. To do this a PCB was developed fortesting the Senior processor together with a Virtex-4 FPGA. Extensive testingwas done on the most important functions of the Senior processor. These testsshowed that the manufactured Senior processor works as designed and that it alonecan perform larger calculations and use external hardware accelerators with thehelp of its various interfaces. / Den första versionen av Senior processorn skapades som en del i ett examensarbe-te under 2007, denna processor färdigställdes och användes i utbildningssyfte påLinköping Universitet. 2008 optimerades flera delar av processorn och utökadesmed extra funktionalitet som del av ytterligare ett examensarbete. 2009 startadeett EU finansierat projekt vid namn MULTI-BASE, som ISYs Datortekniks avdel-ning deltar i. Till deras del av MULTI-BASE projektet valdes Senior processorn attanvändas, efter ytterligare utveckling skickades denna processor för tillverkning. Detta examensarbete hade i uppgift att testa och verifiera de olika funktionernasom Senior processorn har implementerats med. För att göra detta tillverkades ettkretskort som ska användas för att testa Senior processorn tillsammans med enVirtex-4 FPGA. Utförliga tester gjordes på de viktigaste funktionerna hos Seniorprocessorn, dessa tester visade att den tillverkade Senior processorn fungerar somplanerat. Den kan på egen hand utföra större beräkningar och använda sig avexterna hårdvare acceleratorer med hjälp av sina olika gränssnitt.
327

Optimization and Verification of an Integrated DSP

Svensson, Markus, Österholm, Thomas January 2008 (has links)
<p>There is a lot of applications for DSPs (Digital Signal Processor) in the most rapidly growing areas in the industry right now as wireless communication along with audio and video products are getting more and more popular. In this report, a DSP, developed at the division of Computer Engineering at the University of Linköping, is optimized and verified.</p><p>Register Forwarding was implemented on a general architecture level to avoiddata hazards that may arise when implementing instruction pipelining in a processor.</p><p>The very common FFT algorithm is also optimized but on instruction setlevel. That means the algorithm is carefully analyzed to find operations that mayexecute in parallel and then create new instructions for these parallel operations.The optimization is concentrated on the butterfly operation as it is such a majorpart of the FFT computation. Comparing the accelerated butterfly with the unaccelerated gives an improvement of 30% in terms of clock cycles needed for thecomputation.</p><p>In the report there are also some discussions about the benefits and drawbacksof changing from a hardware to a software stack, mostly in terms of interrupts andthe return instruction.</p><p>Another important property of the processor is scalability. That is, it is possibleto attach extra peripherals to the core, which accelerates certain tasks. Aninterface towards these peripherals is developed along with two template designsthat may be used to develop other peripherals.</p><p>After all these modifications, a new test bench is developed to verify the functionality.</p>
328

The production and detection of optimized low-Z linear accelerator target beams for image guidance in radiotherapy

Parsons, David, Parsons, David 22 August 2012 (has links)
Recent work has demonstrated improvement of image quality with low atomic number (Z) linear accelerator (linac) targets and energies as low as 3.5 MV compared to a standard 6 MV therapeutic beam. In this work, the incident electron beam energy has been lowered to energies between 1.90 and 2.35 MeV. The improvement of megavoltage planar image quality with the use of carbon and aluminum linac targets has been assessed compared to a standard 6 MV therapeutic beam. Common electronic portal imaging devices contain a 1.0 mm copper conversion plate to increase detection efficiency of a therapeutic megavoltage spectrum. When used in imaging with a photon beam generated with a low-Z target, the conversion plate attenuates a substantial proportion of photons in the diagnostic range, thereby reducing the achievable image quality. Image quality as a function of copper plate thickness has been assessed for planar imaging and cone beam computed tomography.
329

Untersuchung des Einflusses von Geburtsgewicht und Gewichtszunahme auf die Diabetesmanifestation im Kindesalter: Aufgreifen der Akzelerator-Hypothese

Kuchlbauer, Veronika 13 November 2014 (has links) (PDF)
In der Literatur wird von einem kontinuierlichen, weltweiten Anstieg der Inzidenz des Typ 1 Diabetes mellitus unter Kindern und jungen Erwachsenen, insbesondere in der Altersgruppe der unter 20-Jährigen, berichtet. Die multizentrische Studie EURODIAB untersuchte in den Jahren 1989-2003 die Inzidenz des Typ 1 Diabetes in 17 europäischen Ländern und bestätigte mit deren Ergebnissen diese weltweite Tendenz. Die Akzelerator Hypothese von Wilkin aus dem Jahr 2001 sieht die Ursache hierfür durch einen übermäßigen Gewichtsanstieg bedingt, da auch die Inzidenz übergewichtiger Kinder innerhalb der letzten Jahre zugenommen hat. Demnach sei die Anzahl Betroffener insgesamt gleich, jedoch in jungen Jahren (bis 15 Jahre) erhöht. Folglich sei Übergewicht mit Insulinresistenz ein Triggerfaktor für eine raschere Progression der Erkrankung und würde zu einem vorzeitigen klinischen Ausbruch des Typ-1-Diabetes beitragen. Im Rahmen dieser Dissertation verglichen wir anthropometrische Geburtsdaten von 1.117 Kindern mit Typ 1 Diabetes mellitus, deren Erstmanifestation zwischen 1988 und April 2013 lag, mit einer Kontrollgruppe, die bezüglich Geschlecht, Alter und Schwangerschaftswoche angepasst wurde (n=54.344). Des Weiteren wurden die Kinder mit Diabetes entsprechend ihres Alters bei Manifestation bestimmten Gruppen zugeordnet: G1:0-4,9 Jahre; G2:5 9,9 Jahre; G3:10-20 Jahre. Diese Unterteilung wurde vorgenommen, um festzustellen, ob Kinder, bei denen eine Diabetes Erkrankung früher klinisch manifest wird, zur Geburt bzw. zum Zeitpunkt der Diagnosestellung einen höheren Gewichts SDS aufweisen als Kinder, welche erst in späteren Jahren betroffen sind. Zusätzlich wurden Verlaufsdaten des BMI SDS von 540 Studienkindern vor, zu und nach Manifestation ermittelt und mit einer gesunden Kontrollpopulation (n=134.249) verglichen. Hierbei zeigten Kinder und Jugendliche mit Typ 1 Diabetes im Vergleich zu Stoffwechselgesunden signifikant erhöhte Geburtsgewicht SDS Werte. Es konnte jedoch keine signifikante Abhängigkeit zwischen einer vorzeitigen Diabetes-Manifestation und einem erhöhten Geburtsgewichts bzw. einem erhöhten BMI SDS zum Zeitpunkt der Manifestation gezeigt werden. Ebenso blieb der laut Wilkin zu erwartende Gewichtsanstieg 4 Jahre vor Ausbruch der Erkrankung aus. Kinder mit Diabetes verlieren, wie erwartet, zur Manifestation an Gewicht und erreichen nach ungefähr einem Jahr ihr Ausgangsgewicht. In den Folgejahren sind Kinder mit Typ 1 Diabetes signifikant schwerer als die Kontrollgruppe. Aufgrund dieser Ergebnisse müssen wir die von Wilkin postulierte „Akzelerator Hypothese“ widerlegen.
330

Time dependent material properties of shotcrete for hard rock tunnelling

Bryne, Lars Elof January 2014 (has links)
In this thesis different mechanical properties for shotcrete (sprayed concrete) such as compression strength, bond strength, bending tensile strength, elastic modulus, free and restrained shrinkage as a function of its age was investigated. One of the main issues was to investigate the difference between ordinary cast concrete and shotcrete. Reliable material data for young and hardening shotcrete is scarce which in the past have made such comparisons difficult. Also, less accurate data representative for cast concrete has often been used in numerical modelling and design analyses. The focus of the project has particularly been on the properties bond strength and restrained shrinkage for which two new testing methods has been developed and evaluated. Microstructural studies have also been performed as a complement to the bond strength testing. The bond to rock is one of the most important properties for shotcrete used as rock reinforcement. During the very first time after spraying the physical properties and the bond to the rock depend on the set accelerator and the micro structure that is formed. The investigation of early age bond strength of shotcrete is of great importance both from a production perspective and a safety perspective. The newly developed method was tested and evaluated and proved that it can be used for bond strength testing already from a couple of hours after shotcreting. The bond, or adhesion, depends on several factors such as texture of the rock, the type of accelerator, application technique, etc. In this work the development of the microstructure in the interfacial transition zone (ITZ) and strength of the bond was investigated. The results show that the bond strength is related to the hydration process, i.e. the strength gain of the shotcrete. The early development of the ITZ was here studied using a scanning electron microscope (SEM) making it possible to observe changes over time, before and after proper cement hydration. Restrained shrinkage cracking of shotcrete, especially in the case of shotcrete sprayed on soft drains that are parts of a tunnel lining not continuously bonded to the rock, can be detrimental for the sustainability of an infrastructure tunnel system. Maintenance and repair costs can be high over time. It is shown that the developed test method realistically captures the behaviour of shotcrete drains on hard rock in situ. The method can be used in the evaluation of different technical solutions for avoiding or minimizing shrinkage cracks in shotcreted soft drains. It can also be used to assess the performance of shotcrete fully bonded to a rock surface, with respect to the ability to prevent cracking or to distribute possible shrinkage damage into several fine cracks instead of one wide. / <p>QC 20140526</p>

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